Effects of an industrial mixture of methylated-b-cyclodextrins (RAMEB) in the bioremediation of artificially and aged PCB-contaminated soils.

The bioavailability of polychlorinated biphenyls (PCBs) occurring in aged-contaminated soils influence significantly their biodegradation. In this study, a mixture of methylated-beta-cyclodextrins (RAMEB) was investigated for the capability of improving the PCB bioavailability, and therefore of enhancing the biological treatability of such soils. The aerobic bioremediation and detoxification of several spiked and aged PCB-contaminated soils were proved to be more effective by the addiction of RAMEB, that was found to be non-toxic and slowly biodegradable by the indigenous biomass; in particular, RAMEB seemed to stimulate the growth of PCB-mineralizing bacteria in the soil water-phase. The effects of RAMEB were generally dependent on the a) concentration at which it was applied (optimal dose: 1% w/w), b) physical, chemical and biological properties of the treated soils, and c) treatment conditions (best effects: under conditions providing a high soil homogeneity)